Whip the Vanilla Yogurt Dip: In a medium bowl, beat the softened cream cheese or marshmallow fluff with a hand mixer or whisk until smooth. Add the vanilla Greek yogurt, raw honey or maple syrup, vanilla extract, and optional ground cinnamon. Whisk vigorously for 1 to 2 minutes until the dip is light, creamy, and completely lump-free. Transfer it to a decorative central serving bowl and chill in the fridge while you get the fruit ready.
Prep the Fresh Fruit: Wash all your berries and grapes thoroughly under cold water. Pat them completely dry with paper towels. Doing this keeps extra water from diluting your dip and keeps the platter looking fresh. Peel, seed, and slice your cantaloupe into nice, uniform wedges or cubes.
Assemble the Rainbow Platter: Place your bowl of chilled vanilla yogurt dip right in the center of a large wooden board or a white ceramic platter. Arrange the fruit in distinct, colorful sections radiating out from the center bowl. Put the orange cantaloupe on one side, red raspberries and strawberries next, deep purple blackberries next, and bright green grapes to round it out. Garnish the top of the dip with a tiny drizzle of honey and a fresh sprig of mint.
Serve Cold: Serve it up immediately while it is nice and cold, alongside wooden skewers or small cocktail forks for easy dipping.